Hepatitis C virus internal ribosome entry site (HCV IRES) (HCV IRES)

The Hepatitis C virus (HCV) internal ribosome entry site (IRES) is a highly conserved, complexly folded RNA structure located in the 5' untranslated region of the viral genome (Lukavsky, 2009, Virus Research). It serves as the primary mediator for the initiation of viral protein synthesis, utilizing a cap-independent mechanism to recruit the host's 40S ribosomal subunit directly (Fraser & Doudna, 2007, Annual Review of Biochemistry). This process is critical for the viral life cycle, as the entire HCV polyprotein is translated from a single open reading frame downstream of the IRES (Kieft, 2008, Trends in Genetics). Because the IRES-mediated mechanism differs significantly from the cap-dependent translation used by most host mRNAs, it is considered a high-value therapeutic target for antiviral drug development (Filbin & Kieft, 2009, Current Opinion in Structural Biology). Therapeutic strategies include the use of small molecules, antisense oligonucleotides, and ribozymes designed to bind specific domains of the IRES to induce conformational changes or sterically hinder the recruitment of the translation machinery (Berry et al., 2011, Hepatology). While direct-acting antivirals (DAAs) targeting viral enzymes are currently the standard of care, IRES inhibitors offer a complementary approach that could potentially overcome resistance, though challenges remain regarding specificity and delivery (Parsons et al., 2009, Nature Chemical Biology).

Other names

HCV 5' untranslated regionHCV 5' UTRHepatitis C virus IRESInternal ribosome entry site

Inhibition of viral translation initiation by binding to the IRES RNA structure and preventing the assembly of the 40S ribosomal subunit or inducing conformational changes that block translation.